One of the most severe complications of deep-scaling periodontal therapy is a process called periodontal ankylosis: the formation of a solid bony attachment between alveolar bone and tooth roots. We have therefore asked the question as to how this non-mineralized periodontal ligament space between alveolar bone and root cementum is maintained. In order to determine candidate molecules that might contribute to the establishment and maintenance of a non- mineralized periodontal ligament space facilitated by HERS, we have performed gene array analyses in a tooth movement model featuring simultaneous periodontal tissue regeneration and periodontal ligament maintenance (Holliday et al. 2005). From these screens, ameloblastin emerged as a HERS-related gene product that was significantly upregulated during periodontal regeneration and ligament remodeling. Following this lead, we have performed a number of preliminary studies to test the effect of ameloblastin on the mineralization behavior of periodontal ligament cells. Results from these studies suggested that ameloblastin significantly inhibits mineralization of periodontal ligament cells. Here we propose a series of studies to further investigate the effect of ameloblastin on the mineralization behavior of periodontal ligament cells and to determine how ameloblastin might affect the periodontal ligament in our periodontal regeneration model. [unreadable] [unreadable] Narrative: One of the most severe complications of gum diseases is a process called ankylosis: the formation of a solid bony attachment between jaw bone and tooth roots. Here we will conduct a series of studies to investigate the effect of a unique gene product (called ameloblastin) to prevent ankylosis. These studies might eventually lead to novel cures for gum diseases. [unreadable] [unreadable] [unreadable]